We need to be able to programmatically (via C# or VB.Net) create PDF documents as well as join multiple documents together. It needs to be fully automated and the code needs to execute and create the PDF documents on each user's Windows PC.

Do I need Acrobat and the Acrobat SDK? I looked at some information about the SDK and it looks like it's designed to aid you in creating plug-ins for the Acrobat app, not necessarily used to create PDF's from scratch in your .Net code.